We see in this episode that Picture Picture has almost "magic mirror" capabilities, in that Fred asks it "Picture Picture on the wall. Would you kindly show us all? What Chef Brockett's going to fill that box up with." The picture reveals ingredients for a cake.
This goof appears right before Lady Aberlin sings "It's An Ugly Day:" Rogers can be seen moving behind the Neighborhood wall just to the left of the factory.
This episode is unique in that it closes out with Rogers cleaning the mess in his kitchen while singing the finale song, as opposed to leaving the house.
Mister Rogers: I've never seen anything made like this. You say it's a surprise. Is it a pudding?
Chef Brockett: Sh!
Mister Rogers: My great-grandmother used to say, "You should take an hour to drink one glass of milk."
Mister Rogers: "Dear Mister Rogers. I will be over today to fill this up. Yours truly, Chef Brockett." And there's a little person with a chef's hat on it. Aw, and I was all ready to eat something.